The term "most heliacal" indicates the point at which a star, typically one in the Sirius star system, becomes visible just before sunrise. Synonyms for this phrase include "most visible," "most conspicuous," and "most prominent." Other possible synonyms might include "most brilliant," "most radiant," and "most dazzling," all of which suggest the star's brightness and its ability to stand out against the dawn sky. Alternately, one might use phrases like "most elevated," "most elevated above the horizon," or "most high in the sky" to describe the star's position in relation to the observer's location.